Endoscopes used for such surgery have outer tubes which are placed into the patient's urethra. The optical system allows viewing the field of surgery. The surgical instrument, for instance scissors, tongs or, typically, a high-frequency cutting electrode, allows surgery, specifically, cutting. The main body of the endoscope comprises actuators driving the surgical instrument, for instance to reciprocate it axially. As a rule, the endoscope also comprises fittings for flushing water with which the area of surgery is flushed to achieve better viewing.
As regards endoscopes comprising a pistol grip at the main body, rotating means are known whereby parts of the main body can be rotated relative to the remaining parts of the endoscope. However, the surgical instrument and the outer tube always are mutually non-rotational.
When operating in the bladder, in particular when resecting the prostate gland, the rotational position of the surgical instrument relative to field of surgery frequently must be changed. Illustratively, when operating on the prostate, removal must take place alternatingly on the right, left, top and bottom. When using a known endoscope of the kind mentioned above wherein the surgical instrument is stationary relative to the outer tube, this outer tube therefore must be constantly rotated in the urethra. However, the friction between the outer tube wall and the urethra wall irritates the sensitive mucous lining of the urethra and may lead to injury.